Pneumatic conveyer suction hood



2 -sHEETs-SHEET 2 M. l. DORFAN PNEUMATIC CONVEYER SUCTION HOOD Ll J7 Ll J5 May 5, 1953 Filed July l2, 1951 o M /m a l J a Y l MMM m0 om mz f H l M JH P 5 v w i .y e 4. l 5 0 6 .h Y J l IIILVIL 6 .Ui

Patented May 5, 1953 OFFICE 12,637,60G` TPNEUMTICCONVEYERL SU CTION HOOD 'eMortonLDorfanQ Pittshul'gh*y Pa.-

Application,JllyA 12, 1951,1v Serial No. 236,342

(Cl. 3D2-#581) .4 claims;A

invention relates'tojpneumati'c `conveyor suction` hoods' which are used' for piclringsupv loose materaIV such as"A granularA material and" liber-s, fromamovi'n'gbed ofthat material. Such'ahood isi-shown' in Patent 'No.ZA'QQgSOI..

isamong the objectsA ofthist-invention to pro'- vi'de" a. suction jhood'f which. does `a betterjob` of collex'iiting the/material'that is. to'be conveyed'4 ati/'ay thani earllerhoods', and which does=- it with less' air" velox'zi'ty'andA afsmall'er pressure drop.

In accordance with thisx'inventionsfthe `hood' has apair ofi laterally spaced upright' side: plates', thellower. edges of' which are adapted'to" extend' lengthwise'alonga movingbed of loose materialy tobe. carried awayV by a.pn'euinatic'4 conveyor.. "AF top plate lextends across the space be.- tween theA sideplatesabove their lower edges and forms'with. the' side platespan open bottom pas'- sage"y having` an` air' inlet at vone* end' of@v the; plates and ani air outlet at' their." opposite end'. "An" upwardly curved elbow is connectedv to the" outl'etand'- tothe lower end of a pneumaticconveyorduct allurek Air that isl drawn into the passage inletpicks up materialfrom thezbedmoving length-- wise-'throu'ghthe hood and carries 'itinto the elbow'and then into the duct. Preferably;the top platefispivotally mounted onfa horizontal so thattheheight ofthe inlet can be'izarred.v Also;I it" is desirable' to 'locate the'y vbottom of i the lower. end' ofthe elbowa"A short` distanceI 'above the lower edges ofL the side plates;

The; preferred embo'diment'fI off the invention is illustrated'. inv the' vaccornpanying" 'drawings in Which'Eg. isaimnt" Viewy of a; pai'ror cooperatingfhoods';fFig;.-' 2 isla-vertical section taken orrof Figf', showinglthe hood associated' with a vibrating table; A"Figl 3' ista front viewoi one of the hoods taken 'on the lineiIlIL-III of'Fi'g.; 2;!ariidllg.54E4 is a rearr'viewioi one hood without the 'side plates.

Reterringfto thedrawings, Aa,'vertical"pneu:- matic'r'conveyor duct I' isvlocated'some distance abeve'the lower end of" a longitudinally vinclined table. "The table i'sA of' conventional'desi'gn, having. parallel side-wallsaz connected togetherat theirbtt'om by a bottom wall 3. About half way between ther Ytop and battent ofv 'thea-sidewalls there is a screen: ll` whit-:h` eXtendsacross. the table for supporting a'bed floose material, such as flbersforiv powdered or granular material.Y Separated-asbestos-bers often form'such a bed. -"lhe table isf'reciprocatcdv lengthwise! by anyf suitable means in su'chi a, mannerl as-tdeause the bed on the.- screen to travelA toward the lower end ci thetalole.. i l

"Fronr opposite sidesof the Tower-portion ordnet Fapair-of branch ducts 6 diverge downward'- and terminate in laterally" flared portions which have long, narrow lower ends. The branchducts are provided' with manually adjustable dampers "l, Joined toA thev lower end of each of' these branch ducts? is an elbow 3 that curves downward'` and forward to a point'a 'short distance above the screen near its lower end. The elbow isy rectangular in cross section and its lower endp'reierably lies' in a substantially Verticalplane.

Adjoining the' outer sides ofthe two elbows at the lower" ends are the rear ends of a pair of'parallel'vertical side plates 9. An intermediate side plate lll hasits rear endlocated between the adjacentinnersides of theelbows. The lower edgesv ofthe three sideplates extend up along the screen parallel tov it, but thel upper edges of the platesare inclined upward and forward relative toftheir lower edges soA that the fron-t endsv of the plates are taller than their rear ends.. The threerisi'dey pl'atesare held in position by a pair or parallel angle bars lvll that extend across the fronty andv rear ends' of the bent-over'tops of the plates. The front bar Il is supported-by'rods t2 connected; tothe upper portions of7 the branch ducts 61, and the elbows 8' are supported by' rods t3- connected to brackets Hl' and suspended from any suitable overhead support (not shown). These rodshold. the' three side;A plates in position ywith their' lower edges spaced a short distance above the screen sov that the screen will not ruby against them..

Extending across the space between each pair cfside plates 9 and lil is a top plate l5: o1' vane which has its rear end mounted on a pivot rod i8v extending across the top of the lower end of the adjoining elbow and into the side plates. This permits the'front' endof the top: plate to be adjusted up or down by means' of an adjustable hanger rod l1 that connects the front end ofi theA plate' to the adjacent branch duct. The frontendA of' theI plate is curved upward. Each pair of sideplates `and' the top plate' between them form an open bottom passage l'lavingA an air inletV at. the

front end ofltheplates and an air outlet at thev lower end/ot` the. adjoining* elbow. Although the bottom off this' passage isA open as far as: the hood, is concerned; the screenaa-nd; the bed ot loosemat'erial on i'tvforrn a iioor'for the passage. When itA is desired to raise the topi plates I5 in order toperform clean-out work` or repairs, hanger rods [T can be unhoolred from ducts 6. and hooked onto hooks i8 (Fig. 1) at a higherv level, where bythe!outer` endsr` of: the. plates will be swung upward:v outrof the way.

fln operation: loosexmaterial, asbestos bers for example, is dumped einv the upper end of the table and moves downward over the screen 4 due to the movement of the table. The bers are shaken out over the screen to form a traveling bed, and sand and other foreign particles mixed with the bers shake through the screen onto the bottom wall 3 of the table. As the fibers approach the front ends of the suction hooks and travel down through them, the air drawn in through the hoods by duct I picks up the fibers and draws them through the elbows and up into the branch ducts. The position of the top plates I5 or vanes determines the velocity of the entering air and thereby the distance in front of the hoods that the air currents will start to pick up the bers. Due to the fact that the bed of bers moves lengthwise of the hoods, the bers are exposed to the suction in the hoods for a much longer time than if they were carried transversely across the lower end of a vertical hood having an inlet no larger than the inlets of my hoods. Since the height of the hood inlets disclosed herein has nothing to do with the distance that any given bers in the bed can travel through the hoods, the height of the inlets can be maintained small so that the desired velocity of the air can be obtained without large suction. rIhe velocity likewise need not be great, due to the large area of the bed exposed to the suction.

By the time the bers on the screen have reached its lower end, the only ones remaining on the screen are the clumps of unseparated bers which are too heavy to be picked up by the air currents. It will be noted that the only inlet to each elbow is at its lower end, facing forward. Some air will be drawn into the rear end of each hood through the space between the lower end of its elbow and the underlying screen. This air helps pick up any loose bers that may have passed entirely through the hood.

The reason for using two hoods side by side is well known. They distribute the suction more uniformly across the width of the bed than a single wide hood would do.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specically illustrated and described.

I claim:

1. A pneumatic conveyor suction hood for pi cking up loose material from a moving bed, the hood comprising a pair of laterally spaced upright side plates whose lower edges are adapted to extend lengthwise along the bed, a top plate extending across the space between the side plates above their lower edges and forming with the side plates an open bottom passage having an air inlet at one end of the plates and an air outlet at their opposite end, said plate being positioned to give said passage a height that is undiminished from its outlet to its inlet end, and an upwardly curved elbow connected to said outlet and adapted to be connected to the lower end of a pneumatic conveying duct, the inlet of the elbow facing toward the inlet of said passage, whereby air drawn into said passage inlet will pick up material from said bed and carry it in a substantially straight line into said elbow inlet.

2. A pneumatic conveyor suction hood for picking up loose material from a moving bed, the hood comprising a pair of laterally spaced vupright side plates whose lower edges are adapted to extend lengthwise along the bed, a top plate extending across the space between the side plates above their lower edges and forming with the side plates an open bottom passage having an air inlet at one end of the plates and an air outlet at their opposite end, means pivotally connecting the top plate to the side plates on a horizontal axis near said outlet, means for adjusting the opposite end of the top plate vertically to give said passage a height that is undiminished from its outlet to its inlet end, and an upwardly curved elbow connected to said outlet and adapted to be connected to the lower end of a pneumatic conveying duct, the inlet of the elbow facing toward the inlet of said passage, whereby air drawn into said inlet will pick up material from said bed and carry it in a substantially straight line into said elbow inlet.

3. A pneumatic conveyor suction hood for picking up loose material from a moving bed, the hood comprising a pair of laterally spaced upright side plates whose lower edges are adapted to extend lengthwise along the bed, a top plate 1 extending across the space between the side plates above their lower edges and forming with the side plates an open bottom passage having an air inlet at one end of the plates and an air outlet at their opposite end, and an upwardly curved elbow connected to said outlet and adapted to be connected to the lower end of a pneumatic conveying duct, the inlet of the elbow facing toward the inlet of said passage, whereby air drawn intor said passage inlet will pick up material fromI said bed and carry it in a substantially straight line into said elbow inlet, one end of the top plate being pivotally mounted on a horizontal axis at the top of the lower end of said elbow, andl the opposite end of the top plate being curved upward, said plate being positioned to give said passage a height that is undiminished from its outlet to its inlet end.

4. A pneumatic conveyor suction hood for picking up loose material from a moving bed, the hoodv comprising a pair of laterally spaced upright side plates whose lower edges are adapted to extend lengthwise along the bed, a top plate extending across the space between the side plates above their lower edges and forming with the side plates an open bottom passage having an air inlet at one end of the plates and an air outlet at their opposite end, said plate being inclined upward from the outlet to the inlet end of said passage relative to the bottom of thel passage, and an upwardly curved elbow connected to said outlet and adapted to be connected to the lower endl of a pneumatic conveying duct, the inlet of the elbowv being disposed in a plane substantially perpendicular to the bottom of said passage, whereby air drawn into said passage inlet will pick up material from said bed and carry it in a substantially straight line into said elbow inlet, the bottom of the lower end of the elbow being spaced a short distance above the lower edges of the side plates.

MORTON I. DORFAN. 'y

References Cited in the file of this patent i UNITED STATES PATENTS i l.

Number Name Date 268,303 Smith Nov. 28, 1882 2,499,301 Dorian Feb. 28,

FOREIGN PATENTS Number Country Date 'M 235,114 v Germany Sept'. 17, .1910 

